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– Relapse-free/progression-free survival for NKTR-255 plus CD19-22 CAR-T cell therapy at 12 months was double that of historical controls (67% vs 38%) – – Eight of nine patients achieved complete remission, all without detectable MRD – SAN FRANCISCO, Oct. 17, 2024 /PRNewswire/ -- Nektar Therapeutics (Nasdaq: NKTR) today announced the publication of the first clinical data from a Phase 1 study evaluating NKTR-255 in combination with an autologous bispecific chimeric antigen receptor (CAR)-T cell therapy targeting CD19 and CD22 in patients with relapsed or refractory B-cell acute lymphoblastic leukemia (B-ALL) in Blood, the peer-reviewed medical journal of the American Society of Hematology. NKTR-255 is a novel IL-15 receptor agonist currently being studied in clinical trials in combination with cellular therapies and immune checkpoint inhibitors. NKTR-255 has shown in previous clinical studies that it can proliferate a range of immune cells and augment lymphocyte trafficking.1,2 The data published in Blood showed favorable efficacy with eight out of nine patients (89%) whom successfully received CAR19-22 followed by NKTR-255 achieving measurable residual disease (MRD) negative remission. The study further demonstrated that, at 12 months, relapse-free/progression-free survival for NKTR-255 in combination with the CD19-22 CAR-T cell therapy was double that of historical controls (67% vs 38%). "We are encouraged by these first clinical data that clearly demonstrate the ability of NKTR-255 to potentiate CAR-T cell therapy," said Mary Tagliaferri, MD, Senior Vice President and Chief Medical Officer at Nektar. "Data showed NKTR-255 in combination with CD19-22 CAR-T cell therapy resulted in a 67% 12-month relapse-free survival rate in relapsed or refractory B-ALL and investigators observed significant increases in proinflammatory cytokines and chemokines which suggest lymphocyte trafficking to tissues." The Phase 1 single-center, single-arm dose-escalation study was conducted by Stanford Medicine and evaluated NKTR-255 in combination with CD19-22 CAR-T cell therapy in patients with relapsed or refractory B-ALL (NCT03233854). "While CAR-T cell therapies have transformed the treatment landscape for B-cell malignancies, there remains a significant unmet need to drive durable treatment outcomes as relapse occurs in the majority of patients," said David Miklos, MD, Chief of BMT and Cell Therapy Program at Stanford Medicine, Division of Blood and Marrow Transplantation and Cellular Therapy. The primary outcomes of this study were feasibility and safety. Secondary endpoints were assessed for patients who received NKTR-255 (n=9) and included pharmacokinetics of NKTR-255 as measured by IL-15 levels in blood and efficacy as measured by remission free survival (RFS). Exploratory endpoints included cytokine profiling, CAR19-22 expansion in blood, bone marrow, and cerebrospinal fluid (CSF), and long-term CAR-T persistence. Key findings are summarized below: No dose-limiting toxicities related to NKTR-255 were observed. The most common adverse events in patients receiving NKTR-255 in combination with the CD19-22 CAR-T cell therapy were fevers, chills, and myelosuppression, which were either self-limiting or manageable with supportive care. The toxicities observed with the combination treatment were similar to those seen after CD19-22 CAR-T cell therapy alone. Cytokine and chemokine profiling showed significant increases in IL-15 levels. Increase in CXCL9 and CXCL10 were associated with decreases in absolute lymphocyte counts and CD8+ CAR T-cells in blood, and ten-fold increases CAR-T cells in CSF, suggesting lymphocyte trafficking to tissue. Favorable efficacy was observed in patients with relapsed or refractory B-ALL treated with NKTR-255 in combination with CD19-22 CAR-T. Eight out of nine patients achieved complete remission with or without hematologic recovery, all without detectable MRD. Compared to Stanford's control group previously treated with the CD19-22 CAR-T cell therapy, NKTR-255 when added to the cell therapy increased the 12-month relapse free survival from 38% to 67%. The median RFS for the CAR T cell only cohort was 3.9 months. For the cohort treated with NKTR-255 and the CD 19-22 CAR-T cell therapy, the median RFS has not been reached with over 14 months of follow up. Only three patients who received combination therapy (33%) relapsed, suggesting administration of NKTR-255 to the CD19-22 CAR-T cell therapy helps prevent early disease recurrence. The full citation of this article can be accessed here (Volume 144, Issue 16, Pages 1649-1753). About NKTR-255 NKTR-255 is a biologic that targets the IL-15 pathway in order to activate the body's innate and adaptive immunity. Through optimal engagement of the IL-15 receptor complex, NKTR-255 is designed to enhance functional NK cell populations and formation of long-term immunological memory, which may lead to sustained and durable anti-tumor immune response. In addition to studies in combination with CAR T cell therapies, NKTR-255 is being studied in a Phase 1 clinical trial sponsored by AbelZeta Pharma, Inc., which is evaluating C-TIL051, a tumor-infiltrating lymphocyte therapy, in anti-PD1 resistant metastatic non-small cell lung cancer (NCT05676749). The JAVELIN Bladder Medley study (NCT05327530), sponsored by Merck KGaA, is also ongoing to evaluate NKTR-255 in combination with avelumab as a maintenance treatment in patients with locally advanced or metastatic urothelial carcinoma.(NCT05327530) About Nektar Therapeutics Nektar Therapeutics is a clinical-stage biotechnology company focused on developing treatments that address the underlying immunological dysfunction in autoimmune and chronic inflammatory diseases. Nektar's lead product candidate, rezpegaldesleukin (REZPEG, or NKTR-358), is a novel, first-in-class regulatory T cell stimulator being evaluated in two Phase 2b clinical trials, one in atopic dermatitis and one in alopecia areata. Our pipeline also includes a preclinical candidate NKTR-0165, which is a bivalent tumor necrosis factor receptor type II agonist antibody. Nektar, together with various partners, is also evaluating NKTR-255, an investigational IL-15 receptor agonist designed to boost the immune system's natural ability to fight cancer, in several ongoing clinical trials. Nektar is headquartered in San Francisco, California. For further information, visit and follow us on LinkedIn. Cautionary Note Regarding Forward-Looking Statements This press release contains forward-looking statements which can be identified by words such as: "will," "expect," "develop," "potential," "advance," "anticipate," "can," and similar references to future periods. Examples of forward-looking statements include, among others, statements regarding the therapeutic potential of, and future development plans for, NKTR-255. Forward-looking statements are neither historical facts nor assurances of future performance. Instead, they are based only on our current beliefs, expectations and assumptions regarding the future of our business, future plans and strategies, anticipated events and trends, the economy and other future conditions. Because forward-looking statements relate to the future, they are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict and many of which are outside of our control. Our actual results may differ materially from those indicated in the forward-looking statements. Therefore, you should not rely on any of these forward-looking statements. Important factors that could cause our actual results to differ materially from those indicated in the forward-looking statements include, among others: (i) our statements regarding the therapeutic potential of NKTR-255 are based on preclinical and clinical findings and observations and are subject to change as research and development continue; (ii) NKTR-255 is an investigational agent and continued research and development for this drug candidate is subject to substantial risks, including negative safety and efficacy findings in future clinical studies (notwithstanding positive findings in earlier preclinical and clinical studies); (iii) NKTR-255 is in clinical development, and the risk of failure is high and can unexpectedly occur at any stage prior to regulatory approval; (iv) the timing of the commencement or end of clinical trials and the availability of clinical data may be delayed or unsuccessful due to regulatory delays, slower than anticipated patient enrollment, manufacturing challenges, changing standards of care, evolving regulatory requirements, clinical trial design, clinical outcomes, competitive factors, or delay or failure in ultimately obtaining regulatory approval in one or more important markets; (v) patents may not issue from our patent applications for our drug candidates, patents that have issued may not be enforceable, or additional intellectual property licenses from third parties may be required; and (vi) certain other important risks and uncertainties set forth in our Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on August 9, 2024. Any forward-looking statement made by us in this press release is based only on information currently available to us and speaks only as of the date on which it is made. We undertake no obligation to update any forward-looking statement, whether written or oral, that may be made from time to time, whether as a result of new information, future developments or otherwise. Contact: For Investors: Vivian Wu of Nektar Therapeutics 628-895-0661 For Media: David Rosen of Argot Partners (212) 600-1902 [email protected] Hirayama A. et al. Pharmacodynamic Analysis of CAR-T Cell Persistence in Patients with Hematologic Malignancies Treated with NKTR-255, an IL-15 Receptor Agonist That Enhances CD8 + T-Cells: Preliminary Results from a Phase 1 Study. Poster presented at: 63rd ASH Annual Meeting; Dec 11-13, 2021; Atlanta, GA Altan M. et al. NKTR-255+cetuximab in patients with solid tumors: interim safety and efficacy results from the phase 1b dose-escalation study. Poster presented at: SITC 2021; Nov 10-14, 2021; Washington, D.C. SOURCE Nektar Therapeutics WANT YOUR COMPANY'S NEWS FEATURED ON PRNEWSWIRE.COM? 440k+ Newsrooms & Influencers 9k+ Digital Media Outlets 270k+ Journalists Opted In GET STARTED

A small US and Canadian gene therapy biotech has released a look at data from its experimental bladder cancer treatment, hoping to enter a field that includes CG Oncology, ImmunityBio, Johnson & Johnson and UroGen. EnGene said Thursday that its non-viral gene therapy led to a complete response in 71% of 21 patients assessed so far in the key cohort of its Phase 2 LEGEND trial. It’s one of several drugmakers testing treatments for patients with Bacillus Calmette-Guérin (BCG)-unresponsive, non-muscle invasive bladder cancer, or NMIBC. Known as detalimogene voraplasmid or EG-70, enGene’s therapy is delivered to the bladder using a catheter four times during a 12-week cycle, for up to four cycles. EnGene said the treatment was “generally well-tolerated” and that no patients stopped the study because of drug-related safety concerns. Most side effects were grade 1 or 2 in severity, with two cases — peripheral edema and urosepsis — reaching grade 3. The biotech expects to collect data on about another 80 patients from the pivotal cohort portion of the open-label study before requesting regulatory approval. But enGene said it plans to package the data into a biologics license application in the middle of 2026 — about one year later than originally projected when the company went public by way of a SPAC combination last November. “The original guidance was more of an estimate, not based on experience. Now that we have a number of sites up and going, we see the enrollment coming in, we feel pretty confident about our [new] guidance,” Ron Cooper, who took over as CEO this summer , said in an interview. Merck’s product BCG is the standard treatment for patients with certain forms of the cancer, but the treatment is in shortage and doesn’t help all patients. Merck has said it expects to finish constructing a new facility to make BCG in Durham, NC, by late 2026. ImmunityBio’s IL-15 agonist Anktiva secured FDA approval in certain patients with the cancer in April, about 11 months after originally being rejected . The drug was approved in combination with BCG, however, meaning it doesn’t assuage concerns about the standard-of-care’s ongoing supply constraints. J&J is also working on a so-called “ pretzel ” drug-device combo. And UroGen is looking to treat patients with certain forms of NMIBC with a decades-old chemotherapy delivered as a gel . Last month, it asked the FDA for approval. CG Oncology, meanwhile, reported interim data from its Phase 3 in May, showing that 75.2%, or 79 out of 105 patients, had a complete response at any time to its therapy called cretostimogene grenadenorepvec. In enGene’s Phase 2 pivotal cohort, the complete response rate was 71% at any time, but it fell to 67% at three months and 47% at six months. For comparison, the complete response rate in CG’s Phase 3 was 63.6% at six months , but in a Phase 2 study, that rate was 44% . As it progresses with the rest of the pivotal trial, enGene said it is making protocol amendments to “reflect what’s done in clinical practice,” according to chief medical officer Raj Pruthi, a urological oncologist who joined the company in April after working on bladder cancer at J&J. “One of the amendments we’ve made recently is involving re-resection of T1 tumors,” Pruthi said. Another adjustment, at three months, is allowing for resection and reinduction of therapy for patients who have recurrence. “That reinduction of therapy is something that’s very familiar to us as urologists from the standpoint of that’s what we have done for years with BCG. And other late-stage agents and even ones approved by the FDA have also employed this reinduction paradigm.” CG has said it expects more data by the end of this year and plans to package the results for an approval request to the FDA. The biotech’s immunotherapy deploys a virus to infect and dismantle tumor cells. It had the first and biggest biotech IPO $CGON of the year, reeling in $380 million in January .